Ignition and control means for fuel burners



Sept. l5, 1942. J. c. ENGLISH- -2,296,025 Y IGNITION AND coNTRoLMEANsFon FUEL BURNERS `Filecl June 28. 1939 n. @mmf `@n.5 .m/ @n m AN Y maVm. 1 Q Q l M I A? m.\ n `w\ \bM./\ C N @i M mw #Sm `M `M l W` .m-\ M"hmf.

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lOther ignition systemsehave been proposed `mainburner.` QAnothermportantobject of" my invention is n Patented 115,' 15942V l i uNITI-2DSTATES PATENT OFFICE i" 2,296,025 ,I m `f IGNITION'ANn 'CONTROL MEANSFoa FUEL BURNERS l John Cf English, Cedar Rapids, Iowa, assigner to`Johnson Gas Appliance Company, Cedar Rap- Y ids, Iowa, aY corporationof Delaware Application June 28,1939, serial No. 281,549V

2 claims. lol'. V15s-117.1)

This invention relatesto fluid fuel burners and 2e has particularrelation toan ignitionand control means forsuch burners.

It is\the usual practice in many types of gas heating devices adaptedfor intermittent useto utilize a constant burningpilot lightforfi'gnitirg the gas issuing from the main burner. However there arenumerous diihculties `with'this ignition system, among which are" thecost of the system ma located outside the burner chainber. Another inelectrical ignitlng devices.

`Another object of my invention is to provide an ignition and controlsystem which is ln operative unless there is suiicient gaf. Pressure toopdevices, asfor instance lighting the pilot burner in the fall andturning it out in thesprina;V as? well as lighting it in theevent ofAthe pilot light `going out.,` j Also the pilot light is not altogetherreliable since only a small amount of gas is used and the pilot lightmay go out. Also fouling ofthe light may occur to cause diagreeableodorsand the utilizing electricity for ignition purposes, but

f Ihese Systems have not been altogether satisfactoryfor the reason`that the `switchesr'nay stick or they may be located inthe heatv zoneand corroding of the contacts-'mayoccur. Manual ignition may beemployedof course, butthis entails danger by reason of explosion,asphyxiation and the like, as well as lower efllciency by reason ofthedoors or thelikevnecessary for manual ig,

,nitio'n.` e

' vIn othertypes'of heating systemsvalves are employed for controllingthe flow of fuel, but it i'sjpractically impossible to connect up anysort of electrical system Ato these valves to thereby profor gas burnersand the like whichshall overa tioned'and which willeliminate thenecessity for erate the main burner.

Another object of my invention is to provide means for igniting a gasburner or the like with` out the necessity `of using doors or otherapertures to furnish a means of reaching the burner 'from outside` theheating device.

panying drawing alnd following specifications, fwherein is disclosed asingle exemplary embodiment of the invention, with the understanding,however, that such changes may be made therein as fall within `the scope`of the appended claims, without departing from the spirit of theinvention.

, ,burner, and Y Figure 2 is a schematic drawing showinga- Figure 1 ofthe drawing is a schematicdiagram illustrating one embodiment of myinvention and how it may be used in connection with a gas modified formofthe switch shown in Figure l` Referring ,now to the drawing: Thedevice there shown is particularly suitable for use with gas burners butquite obviously may be modified for other burners and other purposes.

Y The main portion of thecontrol' means is preferably located within theoven or other burner chamber `adjacent thejburner. This main pormanuallighting or alconstan't burning pilot light.

It .i'sanother objectofmy inventionto provide ignitionlandcontrol meansfor automatically lighting` a fluid fuel burner without Idanger ofexplosion or injury to the operator, which means shall be :"foolproof.a`nd in which the faifnreI cf any of the parts ofthe mechanism tofunction` resrltsonly in stopping the series of operations leading toignition of thegasissuing from `the to provide aquick acting ignitionand control `means'infwhichheat `sensitive portions'of thetion includesa body I0, more orless rectangular in form. The body I0 hasa supplyinlet in the lower face thereof indicated at I .V This supply line canof course be brought in from the side as well as the bottom of theblock-like base I0.

The inlet Ii leads into acylindrical chamber I2.

. Concentricwith the outerl chamber I 2, is a smaller inner chamber I3.The wall of the channel between the chambers I2 and I3 is beveled, asindicated at I4, to form a valve seat for a valve The valve is normallyseated against the objecty of my invention is to very materially reducethe amount of wiring required t al* ythe linefconnectlon 43.

` mercury switch 31.

The central has a notch I9 therein for the purpose of receiving the freeend of a bi-metal strip as hereinafter explained.-

A U-shaped bi-metallic member 2l is secured to one end wall of the 'basemember I0 by means of the bolt 22, and the free end of the U-shapedbi-metallic member is received within the notch I8 `of the member I8, asindicated at 23. It is apparent that .differential expansion andcontraction of the two layersv of dissimilar metals, which constitutethe structure of the bi-metallic strip, will cause reciprocation vof Ito raise and lower the valve I4. The bi-metallic strip is so constructedand arranged that heating of the loop of' the strip, as by means of theflame issuing from a pilot burner 24, will cause contraction of the loopto drive the stem inwardly to raise the valve I6 from its seat. Whenthis is done the gasv admittedat the inlet or supply II passes throughthe chamber I2, into the chamber I3, out through the outlet 26, throughthe conduit 21, and out fthroughthe main burner 28.

Ignition for the pilot burner 24 by means including l trode 3l issupported by means of a'bracket 82 fromthe'base I0. l sulated fromthe-bracket. Current for causing i va high voltage discharge through thegap 38 is furnished by means of the step-up transforman electrode 3|.elec- The electrode is of course inerA 34.

The primary of the step-up transformer 34 is terminal 36 to the'body i.or casing of a mercury switch indicated generally y at 31. A connectionis thus made between the grounded by means of the terminal 36 and a poolof electrically conductive liquid, such as mercury, indicated at 38. Anal ternative arrangement, indicated by the dotted.

. lines, `inl the event that a non-metallic switch 'l "casing isemployed,

is to directly connect vthe the valve stem y l I6 fron its'seat y,

is furnishedby means of a chamber I3.

Now itis apparent that when the gas is on to supply gas to the burner28it will first pass into the chamber I2, and from this chamber secondconduit 62 with the inner will pass upwardly to the pilot burner orifice54 .and out throughl the slot 58 of the pilot burner.

Gas will also pass through the conduit 48 into .the chamberVK 44.AInasmuch as this gas is at higher than atmospheric pressure, themercury within the chamber 44 and outsidethe tube 41 '.will be depressedto drive mercury up within the tube 41.'

The mercury within the tube 41, when it reaches a suiliciently highlevel, contacts with the'lowe'r endof the electrode 45 and closes'thecircuit through the primary of the ignition trans- .former- 34.y Thehigh voltage of the secondary winding causes an are across the gap 38 tothe grounded electrode 30 on the body I0 to ignite y the gas issuing.from thepilot burner 21.

`Theburning gas vfrom the pilot burner heats the bi-metallic element 2 Iwhich raises the valve I6 from its seattolpermitggas' to flow into thechamber ,I3 and the main burner.. Assoon as I thisA yoccurs the pressurethe chambers I2 and, I3 is equalizedand consequently the pressure withinthe chambers 44 and 46 of the switch -is also equalized, which permitsthe'mercury 88 v .to seek, its own levelandthus break the contactbetween. the electrode v and `the mercury 38. Breaking 'of theprimarycircuity of-coil 34 stops the discharge.- of electricity across thegap533.

i; Itis apparent that gas is not admitted'to the main burner until thepilot `burner is ignited.

` Ignition of. the pilot yburner occurs only when gas isfadmittedtc thesuppiyinlet il. Assoon as the supplyoffgasvisl cut o, the burning Aofgas Yprimary of the transformer to an electrode 38 Y I extending intothe mercury pool. i The other side of the primary coil is connected I tothe secondary 4I of a step-down power transfurnished by means of Theother side of the secondary coil `4I of the power transformer isconnected to the central electrode 45 of the. This central electrode 45is, conditions, spaced above the mer- `former 42, power being undernormal cury pool 88 so that no electrical contact therewith is made.

. .There are two chambers 44 and 46 within the switch casing 31. Theupper chamber communicates with the lower by means of a tube 41 whichatthe main burnerand at the pilotburner ceases and the thermostat 2|cools to close the valve Iii.l As-soon asthe. valve is closed, gascannot be admitted to the ,main burner unless the pilot i burner isignited. i

My inveritirmV is susceptible to numerous modirlcationsyI mayutilizeonly one transformer and rpass .a .-110 `volt circuit through themercury switch 31, ror may eliminate both transformers and passthecurrent direct through the mercury `switch 31 and electrode 3 Iprojects down from the upper chamber into theV lower chamber and intothe mercury pool 38. electrode 45 projects downwardly rom the insulatedcap 50 to a position within this tube.

' l The'lower chamber 44 is connected by meansL f of a conduit 48 Vto achannel 49 Ain the body III.

The mercury switch 31 is located outside of the oven or other enclosurein which the burner is 5Iy of the enclosure; The conduit or within thebase I0 communicates with the chamber `I2 and is also connected with thepilot burnpassing through the wall er orifice 54. When gas underpressure is present in the chamber I2,

The upper channel 48y it will pass outwardlyA 'through the restrictedorifice 54 and will also setup a pressure in the conduit 48 and thelower chamber 44 of the mercury switch.4

chamber 46 of the mercury switch AlthoughI have described a specific`embodiment of my invention, it is apparent that modifications thereofmaybe made by those skilled in the art. Such modicationsmaybe madewithout tdepartingfrom the spirit and scope of myinvention'asset.forthin the appended claims.

Iclaim asmyinvention: v I l. Inafluidr fuel. burnerv adapted .tobeoperated in arsubstantially .closed combustion space, a valve havinginlet and outlet chambers, a main burnerconnectedwith the y.outletchamber, a pilot burner. connected directly with the inlet Y ychamber,aY means responsiveto. heat fromv the pilot burner foropening the valve,andswitch means-located outside-the 'combustion space and responsive todifferences in fuel pressure ln the inlet andi outlet chambers, -forcontrolling ignition -o the-pilot burner, said pilot burner being..-supplied with fuel-from rsaidinlet chamber independent of .said switchmeans.

2; In afl-fluid Afuel.burner,.a control;l valve having inletv andoutletports, a gas supply line connected to the inlet port, a mainburnerconnected tothe outlet. port,va. pilot burner thermal control.fmeans; activated by-heat `from the pilot is connected burner for.operatingrlthecontrol valve, electric turned i t e Temeon 1 e `3ignitio meafns `for `the -pilot burner;` "al difieren#- tial pressureswtcheonnected with the intake port `and. with the outlet port wherebyanvin`-` crease in pressure differential betweenfuel in the intake andAOutlet ports willy close thefswitchY `to energize the `electricignition means and whereby audecreaselin the pressure diierential will`operi the switch and ie-energize the ignition *l means said pilotburnerbeingiin direct'communiv cation with said supply line" to `receive Vgas`coriy tnuously therefrom `:its long as gas is"supp1ied to i said `gas`supply line regardless of the `position of said ignition mens;

i I@ClaironNGLISH.

